1. Field of the Invention
The disclosed embodiments relate generally to optics and, more specifically, to optical interconnects and communications.
2. Background Information
The need for fast and efficient optical-based technologies is increasing as Internet data traffic growth rate is overtaking voice traffic, pushing the need for fiber optical communications. Transmission of multiple optical channels over the same fiber in dense wavelength-division multiplexing (DWDM) systems and Gigabit (GB) Ethernet systems provide a simple way to use the unprecedented capacity (signal bandwidth) offered by fiber optics. Commonly used optical components in the system include wavelength division multiplexed (WDM) transmitters and receivers, optical filters such as diffraction gratings, thin-film filters, fiber Bragg gratings, arrayed-waveguide gratings, optical add/drop multiplexers and lasers.
Lasers are well-known devices that emit light through stimulated emission, produce coherent light beams with a frequency spectrum ranging from infrared to ultraviolet, and may be used in a vast array of applications. For example, in optical communications or networking applications, semiconductor lasers may be used to produce light or optical beams on which data or other information may be encoded and transmitted.
Additional devices used in optical communications include optical transmitters which are key components in broadband DWDM networking systems and in Gigabit (GB) Ethernet systems. Currently, most optical transmitters are based on a number of fixed-wavelength lasers combined with an external modulator or in some cases a directly-modulated laser. After light produced from a laser is modulated, it is multiplexed with an external multiplexer and then sent to an optical fiber network where it may be amplified or directed by an optical switch, or both. Separate lasers and modulators are used for each transmission channel, since the lasers typically produce a fixed wavelength. The costs of producing lasers and associated components are very high, however, and using separate components for each wavelength of light to be transmitted can be expensive and inefficient.